import math

x1, y1, x2, y2 = list(map(float, input().split()))
d = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print("{:.5f}".format(d)) import math math x1, y1, x2, y2 = list(map(float, input().split())) x1 list(map(float, input().split())) list map(float, input().split()) map float input().split() ().split () input split y1 x2 y2 d = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2) d math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2) math.sqrt math sqrt (x1 - x2) ** 2 + (y1 - y2) ** 2 (x1 - x2) ** 2 x1 - x2 x1 x2 2 (y1 - y2) ** 2 y1 - y2 y1 y2 2 print("{:.5f}".format(d)) print "{:.5f}".format(d) "{:.5f}".format "{:.5f}" format d x1, y1, x2, y2 = list(map(float, input().split())) list(map(float, input().split())) x1 y1, x2, y2 = list(map(float, input().split())) list(map(float, input().split())) y1 d = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2) math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2) d y2 = list(map(float, input().split())) list(map(float, input().split())) y2 x2, y2 = list(map(float, input().split())) list(map(float, input().split())) x2
import math

x1, y1, x2, y2 = list(map(float, input().split()))
d = math.sqrt((x1 - x2) ** 2 + (y1 - y2) ** 2)
print("{:.5f}".format(d))